As the nation’s top spies prepared to brief President Obama and President-elect Donald Trump on Russian interference in the 2016 election, they faced an excruciatingly delicate question: Should they mention the salacious allegations that had been circulating in Washington for months that Moscow had compromising information on the incoming president?

Ultimately, they concluded they had no choice. A 35-page dossier packed with details of supposed compromising personal information, alleged financial entanglements and political intrigue was already in such wide circulation in Washington that every major news organization seemed to have a copy.

“You’d be derelict if you didn’t” mention the dossier, a U.S. official said. To ignore the file, produced by a private-sector security firm, would only make the supposed guardians of the nation’s secrets seem uninformed, officials said, adding that many were convinced that it was only a matter of time before someone decided to publish the material.

Their decision appears to have hastened that outcome, triggering coverage of politically charged allegations that news organizations had tried to run down for months but could find no basis for publishing until they were summarized and included alongside a highly classified report assembled by the nation’s intelligence services.

U.S. officials said Wednesday that the decision had been unanimous to attach the two-page summary of the dossier to a sweeping report on Russian election interference commissioned by the White House and briefed to Obama, Trump and congressional leaders.

A U.S. official who spoke on the condition of anonymity said the nature of the summary “was fully explained” to Trump on Friday and “put into context.”

But U.S. intelligence officials appear to have been caught off-guard by the fallout, including a blistering attack by Trump, who accused spy agencies of engaging in Nazi-like tactics to smear him.

In an effort to contain the damage, Director of National Intelligence James R. Clapper Jr. said he spoke with Trump on Wednesday and “expressed my profound dismay at the leaks that have been appearing in the press.”

Clapper said in a statement issued late Wednesday that he told Trump that the allegations had come from a “private security company,” that U.S. spy agencies had “not made any judgment that the information in this document is reliable.”

“However, part of our obligation is to ensure that policymakers are provided with the fullest possible picture of any matters that might affect national security,” Clapper said.

(Sarah Parnass,Glenn Kessler/The Washington Post)

Clapper, CIA Director John Brennan, FBI Chief James B. Comey and National Security Agency Director Mike Rogers all concurred that both Obama and Trump should know that U.S. spy agencies were aware of the claims about compromising information on Trump and had investigated or explored them to some degree.

U.S. officials emphasized that the summary was merely an annex to the main report, that the allegations it contained have never been substantiated and did not appear in the main body of the report or influence its conclusions that Russia sought to sabotage the 2016 race and help elect Trump.

But linking a collection of unsubstantiated allegations to a classified report that is supposed to convey the intelligence community’s firmest conclusions about Russian election interference has blurred the distinction between corroborated intelligence and innuendo.

Former U.S. intelligence officials described the inclusion of the summary — drawn from “opposition research” done by a political research firm — as highly unusual.

“It would be extraordinary if not unprecedented to bring to the attention of a president and ­president-elect a private document for which you had no reason to believe the allegations made in it,” said Michael Morell, the former deputy director of the CIA and a supporter of Democratic presidential nominee Hillary Clinton.

Spokesmen for the CIA, FBI and the director of national intelligence declined to comment.

“I think it was disgraceful, disgraceful, that the intelligence agencies allowed any information that turned out to be so false and fake, out,” Trump said, referring to a burst of headlines over the past two days about the dossier. “That’s something that Nazi Germany would do and did do.”

The material in the dossier was assembled by a former British intelligence officer, Christopher Steele, whose security and investigations firm was hired to assist a political research firm in Washington that was initially working for Trump’s opponents in the Republican primaries but later offered its services to Democrats, according to individuals familiar with the matter. Steele’s role was first reported Wednesday by the Wall Street Journal. Since 2009, he and another former British intelligence officer have jointly operated a Britain-based firm called Orbis Business Intelligence. He could not be reached for comment Wednesday.

The dossier was provided to multiple news outlets, including The Washington Post, which pursued numerous leads, including overseas, but could not substantiate its allegations.

The document was also at some point delivered to the FBI. Sen. John McCain (R-Ariz.) acknowledged in a public statement Wednesday that late last year he had “received sensitive information that has since been made public” and, unable to assess its accuracy, delivered the file to Comey.

Other officials said that the FBI had obtained the dossier even before McCain’s involvement and that U.S. officials had met with Steele, the former British spy, at least twice — once in August and again in mid-October, after Clapper had released a public statement accusing Russia of interfering in the election.

Those meetings were part of a broader effort by the FBI and other agencies to evaluate the claims about Russia and compromising material on Trump. The dossier also included claims of ongoing, unexplained contacts between members of Trump’s inner circle and allies of the Kremlin. The status of that inquiry is unclear.

In Senate testimony Tuesday, Comey said that “we never confirm or deny a pending investigation.” The line drew a reaction of disbelief from some lawmakers who have been sharply critical of Comey’s decision during the election to discuss the bureau’s probe of Hillary Clinton’s email use.

“The irony of your making that statement here I cannot avoid,” said Sen. Angus King (I-Maine).

Although Comey was one of only four senior officials involved in the decision to include the two-page summary, some in Washington were quick to see that move as another political misstep by the FBI chief — calling arguably unnecessary attention to allegations against a major political figure.

U.S. officials have offered conflicting accounts of what the meetings with Steele accomplished. A senior official said Tuesday that while the allegations in the two-page summary could not be corroborated, it was included in part because the sourcing was seen as reliable.

Others disputed that and said that it would be difficult, if not impossible, to evaluate Steele’s claims without getting detailed information about his sources in Russia, information he is seen as unlikely to be willing to share.

A former senior U.S. intelligence official also questioned his ability to maneuver in Russia and gain access to high-level officials with ties to the Kremlin or Russian President Vladi­mir Putin.

“How did this former British intelligence officer talk to all these Russian officials and not get arrested for espionage?” the former official asked. Steele’s identity and association with his investigations firm are public, and are almost certainly known to Russian counterintelligence.

“They would have been all over him,” the former official said. “There are aspects of this [dossier] that are believable when you read it. There are other aspects that aren’t.”

Some details would seem relatively easy for the FBI to assess, including meetings between close associates of Trump and Putin allies.

But a senior law enforcement official acknowledged that other claims — including sweeping characterizations of relationships and rivalries inside the Kremlin — are more elusive. “This is not something we can validate or check out,” the official said. “It’s the view of people in Russia. It’s not like we can go out and determine its veracity.”